With the development of communication technologies, mobile terminals such as smart phones are becoming more and more popular. People use the mobile terminal such as taking pictures, chatting, playing games. Because more and more mobile terminal functions are required, more and more devices are mounted inside the mobile terminal. In particular, the more and more devices are mounted on one side of the mobile terminal where a screen is mounted. Therefore, in a case when a size of the mobile terminal does not change, a display area of a display screen is often sacrificed, so that the display area of the display screen becomes smaller.